CASE 13962 Published on 18.09.2016

Appendiceal metastatic neuroendocrine tumour


Abdominal imaging

Case Type

Clinical Cases


Marta Reis de Sousa, Ana C Vieira, Madalena Pimenta, Isabel Vidal

Centro Hospitalar Entre o Douro e Vouga,
Santa Maria da Feira;
Hospital do Espirito Santo, Évora;
Centro Hospitalar São João, Porto

62 years, male

Area of Interest Abdomen, Gastrointestinal tract, Cardiovascular system ; Imaging Technique CT, MR, Nuclear medicine conventional
Clinical History
A 62-year-old man was admitted in the emergency room for right quadrant abdominal pain. He was under diagnostic investigation for cardiac failure in our institution. The patient also reported a few months of diarrhoea and flushing.
Imaging Findings
Computed tomography performed after endovenous contrast administration depicted a diffusely thickened appendix, periappendiceal fat stranding and adjacent enlarged lymph nodes. Two liver lesions were also present, with enhancement, heterogeneous, with gross calcifications. A mesenteric nodular lesion with calcifications was also present. In the thorax enlargement of the right cardiac chambers was seen.
Primary appendiceal tumours are uncommon neoplasms, often leading to luminal obstruction and presenting with signs and symptoms of acute appendicitis in 30-50% of the cases [1]. Appendiceal tumours may also be asymptomatic, incidental findings, or, rarely, lead to intussusception, a palpable mass or gastrointestinal bleeding. [1]

Neuroendocrine tumours are the most frequently appendiceal neoplasms (up to 80% [1], and although previously considered the most frequent location for gastrointestinal NETs, recent reports show a much lower number, representing only 6% [4].

Neuroendocrine tumours or carcinoids are rare neoplasms that belong to a diverse group of tumours arising from the cells of the diffuse endocrine system, and consequently can produce hormones and protein products, leading to specific clinical symptoms. There are two histologic types of appendiceal neoplasms, the classic type and the goblet-cell type, the last type being more aggressive [3].

NET of the appendix are usually small (less than 1cm) incidental findings, and even in patients presenting with acute appendicitis, the tumour is often not the cause of the obstruction [1].

CT is the imaging modality of choice whenever an appendiceal mass is suspected, although CT may not depict NETs because of their small size [4]. A larger tumour may be depicted as a soft tissue mass, with or without calcification.

Metastatic disease has CT features similar to those of small bowel carcinoid tumours, the most frequent locations being the peritoneum and the liver [4]. Most metastases are hypervascular, and like the primary tumour, large lesions may become necrotic and may calcify.

Carcinoid syndrome is rare, and more frequently present with metastatic disease, manifesting with flushing sweating, bronchospasm and diarrhoea.
Carcinoid heart disease occurs due to right-sided valve fibrosis, with consequent regurgitation, leading to right heart failure. In these patients right atrial and right ventricular enlargement is present in up to 90% of cases [2].

Nuclear imaging aids in staging of the disease, through the use of labelled somatostatin analog ocreotid (ocreoscan), with sensitivity in detecting the primary tumour and metastasis reported to be up to 90%.

Appendiceal NET usually have an indolent course with a very good prognosis [3]. The presence of metastasis and carcinoid syndrome is exceedingly rare [3], although it was the case in our patient.
Differential Diagnosis List
Appendiceal carcinoid with mesenteric and liver metastasis, associated with carcinoid syndrome.
Appendiceal carcinoid with mesenteric and liver metastasis.
Acute appendicitis in a patient with liver and mesenteric metastasis of an occult primary neoplasm.
Acute appendicitis in a patient with primary mesenteric GIST and liver metastasis.
Final Diagnosis
Appendiceal carcinoid with mesenteric and liver metastasis, associated with carcinoid syndrome.
Case information
DOI: 10.1594/EURORAD/CASE.13962
ISSN: 1563-4086